Department of Civil, Chemical, Environmental and Materials Engineering (DICAM), University of Bologna, Bologna, Italy.
Research Institute for Ground Water, National Water Research Center, Cairo, Egypt.
Integr Environ Assess Manag. 2020 Nov;16(6):920-933. doi: 10.1002/ieam.4277. Epub 2020 May 28.
In the Nile Delta, a complex network of canals collects drainage water from surface-irrigated fields but also from municipal wastewater. The goal of this work was to assess the technical, environmental, and financial feasibility of the upgrade of a drainage canal (DC) into either an in-stream constructed wetland (ICW) or a canalized facultative lagoon (CFL), in order to produce a water reusable in agriculture according to Egyptian law. The model-based design of the proposed technologies was derived from field experimental data for the ICW and laboratory data for the CFL. Both technologies, integrated by a sedimentation pond and a disinfection canal, led to the attainment of the water quality standards imposed by Egyptian Law 92/2013 for the reuse of drainage water. The life cycle assessment indicated that the upgrade of an existing DC to either an ICW or a CFL results in an extremely small environmental burden, ≤0.3% of that of a traditional activated sludge process. The cost-benefit analysis (CBA) was based on the assumptions that 1) farmers currently irrigate a nonfood crop (cotton) with the low-quality drainage water present in the DC, and 2) thanks to the upgrade to a ICW or CFL, farmers will irrigate a food crop characterized by a higher market price (rice). The CBA indicated that the DC upgrade to an ICW represents an attractive investment because it leads to a financial rate of return >10% over a wide range of cotton market prices. Conversely, the upgrade to a CFL is less attractive due to high investment costs. In conclusion, the upgrade of DCs to ICWs appears a promising option for the treatment of drainage canal water in the Nile Delta, thanks to the high pollutant removal performances, low cost, and negligible environmental burden. Integr Environ Assess Manag 2020;16:920-933. © 2020 SETAC.
在尼罗河三角洲，一个复杂的运河网络收集地表水灌溉农田的排水，但也收集城市废水。这项工作的目的是评估将排水渠（DC）升级为溪流构建湿地（ICW）或渠化兼性池塘（CFL）的技术、环境和财务可行性，以便根据埃及法律生产可用于农业的再用水。所提出技术的基于模型的设计源自 ICW 的现场实验数据和 CFL 的实验室数据。这两种技术都集成了一个沉淀池和一个消毒渠，从而达到了埃及 92/2013 号法律规定的再用水排水质量标准。生命周期评估表明，将现有的 DC 升级为 ICW 或 CFL 只会导致极其微小的环境负担，仅为传统活性污泥工艺的 0.3%。成本效益分析（CBA）基于以下假设：1）农民目前用 DC 中现有的低质量排水灌溉非食用作物（棉花），2）由于升级为 ICW 或 CFL，农民将灌溉具有更高市场价格的食用作物（水稻）。CBA 表明，将 DC 升级为 ICW 是一项有吸引力的投资，因为它在广泛的棉花市场价格范围内导致超过 10%的财务回报率。相反，由于投资成本高，升级为 CFL 的吸引力较小。总之，由于具有较高的污染物去除性能、低成本和可忽略不计的环境负担，将 DC 升级为 ICW 似乎是尼罗河三角洲处理排水渠水的有前途的选择。
